Excess-wattmeter.



A. w. BURKE. EXCESS WATTWIETIR.

APPLICATION FILED MN.2!, 1914- 1,175,508. l Patented Mar. 14,1916.

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' is a specification.

' My invention relates to recording wattf cess of acertain predetermined value. The A .ALFRED w. BURKE, or WILMINGTON, DELAWARE.

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Application filed anuary 21, 1914; Serial No. 813,494.

To all whom t may concern.'

Be it known that I, ALFRED W. BURKE, aA l meters, such as are used on alternating current circuits, and has for its obJect to record only the'electrical energy.- consumed in exmeter is especially intended for use on circuits where the consumer is charged a flat rate forl a limited maximum consumption,`

and is designed `to registerlonly the electrical energy that may be used in excess of the flat rate value, and not to register during the vtime the energyi consumed equals or is less than the value contracted for.

Many devices are in common use having in view the'object of notifying a consumer when the maximum current is vbeing consumed; these devices generally resemble circui breakers, and operate by making and breaking the circuit, and are so connected in the circuit as to lcause the lights to iiicker when the current exceeds the predetermined amount. The contact-points in such apparatus frequently give rise to defective connec tions, causing irregularities in the servicei It is to he observed that with devices of this character, the amount of current the consumer can take is limited, and further that the revenue the central station obtains is also limited.

One object of my invention is toeliminate all make-and-break devices, and to allow the consumer to use an increased quantity of current, measuring only the eigcess current used. In my invention, this result may be accomplished byl acting on the armature of the watt-meter with a magnetic flux equal to and opposite in direction to that generated by the usual series coil of the watt-meter,l when the contracted quantity of electricalv energy is being conliliv 'series Vcoil in the watt-meter will have,

, sumed, in such l a manner as to balance and neutralize the flux generated by the series coil when the speciied current is passing.

Thus,if a consumer contracts for two hunto be supthe current rPhe at tired-,watts of electric energy,

4plied 'at say one hundred volts, .contracted for will be two amperes.

A :for 1s passing.

two amperes, 2 X ampere-turns; and the Patented lidar. ldjgi.

neutralizing magnetic ux will be generated by a coil also having 2 X ampere turns; the meter therefore ywill not register. If the current consumed reaches two and one-half amperes,.the series coil will generate a magnetic iiux equal to 2.5 X ampere-turns, while shaft of the rotating armature, and a fixed coperating pawl preventing' its rotation in the reverse direction. In place of the pawl and ratchet, any of the well known equivalent intermittent-grip devices, such as l a strap and dog, or ball, may be used. An-

other way of accomplishing the same re sult is to wind a transformer with three coils, one of which is in series with the line and carries the fullv current. A second coil is of many turns and is connected in shunt to the' line; this coil has a predetermined value and its Aflux just neutralizes n i and balances the iiux generated by the series current when the current contracted Any excess of-current induces an E. M. F. in the third coil, the resulting current passing through the series coil of the watt-meter. vAnother way of accomplishing the same resultl is by balancing the E. M. F. at the terminals` of the series coil of the watt-meter by l an applied E. M. F. opposite in direction and of a value equal to that normally applied to the series coil when the current contracted for is passing.a Thus, in the illustrations above given, with two amperes passing,fthe E. M. F.' at the terminals of the series coil will be Y-volts; the applied neutralizing E. vM. F. Yshould therefore also have the value of Y-volts. With an increase in current consumption' the E. M. F. at the series coil will equal nred, it causing a current to pass the series coil in such a direction vthat it produces aI proportion to its lvalue.

`,Inj/the.drawings,---Figures'i1 and 2. are

diagrams shbwing thev electrical connections vfor the Watt-'meter in which a predetermined.

' neutralizing magnetic iux is used to control the operation of the meter; Fig. 3 is a diagramshovving a method of applying'a current of a-value only equal to the excess. current consumed, to the series coil ofthe Wattmeter; Figs. i-and 5 arediagrams showing electrical connections for the :Watt-meter in which a predetermined neutralizing E. M.. j

F. is applied to the series coil to controlthe 1.5. operation of the meter; and Fig. 6 shows a' pawl and ratchet device applied to the armature shaft to prevent the meter fromv .rotatingfin the reverse direction. 4 AIn Fig. 1, currentfrom the service mains 11'- isutilized to operate lamps-or other translating devices 12. The Watt-meter, shown diagrannnatically at W, contains the usual shunt coil 13 and series coil 14. An independent transformer 15 generates a second- A ary current of constant value which is passed through the neutralizing coil 16, its ampere turns, and therefore itsmagnetic iux, being equal to and opposite to that of the series coil 14 when the current contracted for. is passing. Underthese conditions, there will be no pull exerted upon the armature of the Watt-meter, andconsequently it Willnot register. When the current consumed exceedsb thevalue contracted for, the ampere- 'turns of the series coil 14 will exceed that of the coil 16, and the magnetic Iiux due to the excess ampere-turns will exert a corresponding-pull upon thearmature, proportional to the excess ampere-turns. With currents of ,less value than that contracted for,

the tendency would be ,for the armature to rotate'in the. opposite direction; this, however, is prevented by its being mechanically "checked:

- In Fig. 2, the neutralizing coil,y 17 consists of a'shunt coil of many turns, having a total number of ampere-turns equal to that ofthe series coil 18 when the current of a value contracted for is beingu'sed. The coil 17 is. placed inthe Wattmeter, and. in suchrelation to the series coil and the armature, veither by being superimposed, or by so locating that the tendency of the armature to rotate is controlled by the resultant pull of the two coils. y With a current in excess of that contracted for, the excess ampereturns in series coil 18 operates the armature; when a current of the value contracted for is passing, the magnetic forces are balanced, and there is no rotation; with currents of less value, reverse rotation of .the armature is prevented mechanically.

In Fig. 3, the series coil 21, Whlch carries the'current consumed, constitutes one primary coil of a three-.coil transformer; shun-t the series-coil 24e of the Watt-meter.

coil 22, constituting a second primary coil thereof, is so designed that lits ampere-turns neutralize and balance the ampere-turns of coil 2l when the current contracted for is passing through `coil 21; vcoil 23 constitutes 70 the secondary circuit, and is connected to When the current Acontracted for is passing, no current is induced. in coil 23,'since coils 21 and 22lneutralize each other; when an ex- 75 cess current is passingthrough coil 21, a current is induced in coil 24: due to the diiference in the ampere-turns in coils ,21 and 22, this induced current passing through coil 24 of the Watt-meter, and this, in con' 80 junction .with the shunt-coil 25, operates the Wattuneter.

i In Fig. 4, the current 'in the consumers circuit passes through the series coil 27 in the Watt-meter, which contains also the 8 5 shunt coil '28. Shunted across the con- 'sumers mains is a step-down transformer coil 31to that of coil27 being. such. that the 95 passage of the main current through coil 27 is opposed and neutralized when itequals or is less than thequantity. contracted for; When it exceeds this amount, the E. M. F. at the terminals of coil 27 exceed that of coil. 3l, and the excess current actuates the Watt# meter proportionally to the amount of the excess only; the main current other than the y excess passing around through coil 31.

InFig. 5, the main current passes through the series coil 34 of the Watt-meter, containing also the shunt coil Connected across the consumers mains is the auto-transformer 36, of many turns, a section of whichl 37, consists of relatively coarse Wire, andis vso proportioned that the E. M. F. at itsteri minalscquals that at the terminals of the series coil 34 when the current contracted for is consumed. The section 37 is so con-I nected to the coil 34 as' to oppose andneuf tralize the passage of the maincurrent when the latter equals or is less than the' current contracted for. When the main current ex,.- ceeds the specified quantity, the E. M. F. at the terminals of coil 34. exceeds that at the terminals of coil v37, and the excess current passes through coil 34, actuating. the Wattn meter Vproportionally to its 'quantityg the remaining part of the current consumed (the current contracted for) passing through coil 37. v In each of the above illustrations, a resistance R is connected in that part of the circuit which is the source of the neutralizing'current. This resistance may be varied at will, and is for the purpose ot adjusting the current to its required value. In lieu oi a resistance, a reactance may be used.

In all the above illustrations, there lWould be no tendency for the Watt-meter to operate when the current Contracted for is being consumed; With currents of less value, the Watt-meter. would operate in the reverse direction, this, however, is prevented by the useoi a suitable brake such as an intermittentgrip device, a paWl-and-ratchet l0 ,being shown attached to the spindle 4l 'of the armature 42. Any other equivalent device, either mechanical, electrical, or magnetic, may be used to accomplish the same f result.v

To the armature spindle il is connected a suitable registering mechanism 43.

I claim l. In a system of measuring electric currents, a lseries coil, a transformer, one section of said transformer connected so as to constitute a neutralizing and balancing agent lto said series coil, and a rotating element arranged to be'actuated by the component of a current to be measured in said series coil in excess of .that neutralized and baln anced by said transformer section.

2. ini an apparatus for measuring elec tric currents, a Watt-meter, a series coil therein, la transformer connected across the mains carrying the current to be measured, and a section of said transformer connected to the terminals of saidseries coil.

3. In an apparatus `for Vmeasuring electric currents, a watt-meter, a series coil therein, an A auto-transformer connected across themains carrying the current to be measured,and a section of said auto-transf 'former .connected to the terminals of` said series coil. Y Y

. 4. In an apparatus for measuring elec tric currents, a watt-meter, a serles coil therein, a transformer connected across the mains carrying the current to be measured, a section of said transformer connected to the terminals of said series coil, and means to prevent said Watt-meter from registering in the Wrong direction.

5. The method of measuring electric currents, which comprises applying to a meas uring instrument ycoil a balancing electric current producing effects on said instru-V ment coil equal and opposite to the eii'eets Copies of this patent may be obtained for terinined current strength.`

,to be measured through a coil in series With ve cents each, by addressing thecommissionex: of Patents, Washington, D. G.

`ing electromotive force to the terminals of said coil equal to the difference of potential at the terminals of said coil when a current of predetermined strength is passing, thereby neutralizing and balancing the eects of said predetermined current strength, and actuating a movable element in said instrument by the current in excess of said prede- 7. The method of measuring electric currents, which comprises passing the current Vto be measured through a coil in series 'With translating devices, passing a current through a transformer coil in shunt with said translating devices, applying an `opposing current from said transformer to'said.

series coil, thereby neutralizing and balancing a predetermined current strength in said series coil, and actuating a'movable element'in a measuring instrument by the current in said series coil in excess of said predetermined current strength.

8. The method of measuring electric currents, which comprises passing the current translating devices, passing a current through an auto-transformer in shunt with said translating devices, connecting a section of said auto-transformer'to said series coil and thereby neutralizing and balancing a predetermined current strength in said series coil, and actuating a movable clement in a measuring instrument with a current in excess of said predetermined current strength.

n testimony whereof I aiiix my signature in presence of two Witnesses.

ALFRED W. BURKE.

Witnesses: i

ALFRED W. GRnGG,

JAMES `W. RoBEnTson. 

